Firearm



uf 23, 3929- K. BERGMANN ET A1.

FIREARM Filed Jan. 27, 192s 2 sheets-sheet 1 July 23, 1929- K. BERGMANN ET A1.

FIREARM 2 Sheets-Sheet 2 Filed Jan. 27, 1928 Patented July 23, 1929.

PATENT KAREL BERGMANN, OF PRAGUE, AND JOSEF OTTOMANSKY, OF PRAGUE-ZIZKOV, CZECHOSLOVAKIA.

FIREARM.

.Application led January 27, 1928', Serial No. 249,990, and in Czechoslovakia January 15, 1927.

This invention relates to means for securing automatic fire arms of small calibre to fixed mountings of the kind comprising an elastic recoil absorbing device, adapted to absorb a great deal of the force of the recoil arising from the discharge of the firearm, thereby making it easier to keep the aim of the weapon when shooting.

This is particularly important in the case of the so-called light machine guns, which are almost universally gas-operated, in order to reduce the weight to a minimum, in contradistinction to recoil-operated machine guns, such as Maxim guns, which as a rule are of heavier construction.

Since in these light automatic fire arms the whole force of the recoil, amounting to about 1600 kilograms, is unabsorbed, not even being utilized in any way for operating the reloading mechanism, they cannot be fixed to an ordinary machine-gun mounting, as otherwise elastic deformations of the mounting would arise, which would result in very considerable ldeflection of the projectile from the original direction and thus would give an inadmissible spreading of the fire.

But if gas-operated machine guns are to be used :for the purposes for which heavy machine guns are generally used now, such as for overhead covering fire for advancing troops, it is absolutely necessary to employ a mounting with guide rail and segmental rack such as are used with heavy machine guns. The full force of the recoil, however, only acts on the mounting for rather less than 0.002 second during each shot, that is, during the time the ball is in the barrel.

One object of the present invention is to provide means for enabling light machine guns to be employed in conjunction with mountings of the kind referred to.

Another object of the invention is to provide means for enabling the gun to be fired with reduced rapidity.

A further object of the invention is to ensure that the gun will only be fired in its run-out position.

The invention consists in a connecting piece for securing automatic fire arms of small calibre to fixed mountings, comprising in combination a part adapted to be rigidly but releasably secured to the mounting, a part adapted to be rigidly but releasably secured to the gun, elastic recoil absorbing means connected to said parts and adapted to permit the gun to move rearwardly with respect to the mounting under the force of the recoil after each shot and to return the gun to its original position with respect to the mounting, a grip and a trigger mechanism on the part of the connecting piece secured to the mounting, said trigger mechanism having a member movable into engagement with the trigger of the gun, so as to actuate the gun trigger on the gun moving into its runout position. The recoil absorbing means takes up the instantaneous shocks, so that the mounting may be of much lighter construction without being subjected to excessive deformation.

The trigger mechanism of the connecting piece is capable of adjustment so as to enable it to fire the gun either immediately the latter reaches its run-out position or after a short delay. The member which engages the trigger of the gun is moved out of the path of the latter after a shot is fired so as to remain inoperative during the recoil and is only returned after the gun reaches its extreme forward position, the trigger mechanism of the connecting piece being adjustable so as to enable it to fire the gun either immediately the latter reaches its run out position or after a short delay.

The run out movement of the gun is checked by means of a brake cylinder having an adjustable throttling outlet for the escape of' the fluid compressed therein during the forward movement of the gun, and by suitable adjustment of this outlet, the speed of firing of the gun can be varied.

One constructional form ofthe connectingpiece is shown by way of example in the accompanying drawings.

Fig. 1 is a longitudinal section of the whole mechanism,

Fig. 2 a longitudinal section through the front part on an enlarged scale,

F ig. 3 a longitudinal section through the rear part,

Fig. 4 a cross section through the connecting pin of the bell-crank lever,

Fig. 5 a cross section through the pin of the trigger or guide rods, and

Fig. 6 a diagram showing various positions of the IOd gear.

The cylinder 1 is connected by means of a footstep journal 2 and a ball journal 3 with an immovable mounting, which is not shown ing the drawing, and which may be constructed with a toothed segment and slide rail like the mountings that are usual for heavy machine guns.

In the interior of the cylinder 1 is fitted an inner cylinder or hollow piston 4 constituting the moving part of the connecting piece, which in its turn contains an inner piston 5, which is rigidly connected with the A cylinder 1 by means of a key 6. The piston 4 is thickened in front and to itis secured, b

means of screws for example as shown, a sa dle 7, which is provided with suitable means such as a strap for securing the machine gun to the connecting piece, said strap being attached to the saddle 7` and passed round the feet 13 of the folded back supporting fork of the machine gun. Only the axis 8, 9 of the gun and the parts 10, 11, 12 shown in broken lines are indicated in the drawings. The rear end of the machine gun, where the trigger 14 is located, is placed in suitable recesses in the rear end of the piston 4. These recesses or corresponding lugs are variously arranged in different cases according .to the type of machine gun employed. An exact fitting ofthe machine gun and its firm seating in the recesses is the most important condition, Ias hereinafter explained, for attaining the desired object. These recesses are arranged in the tubular piston 4 in such a way that it is possible to pull through two symmetrically provided apertures 15 in the rear end of the piston a strap which passes round the handle 12 of the machine gun which is only shown in dotted lines in the drawings, the belt not being shown at all),-

so that the machine gun is very firmly connected with the tubular piston 4 by means of these two devices.

After each shot the machine gun moves backwards, together with the piston 4. Air is thereby compressed in the space between the inner piston 5, which is ground in, and the end of the tubular piston 4, and in addition a helical spring 17, which is connected by means of a bolt 18 and the key 6, firmly seated in the outer tube 1, is stressed. .As soon as the dynamic effect of the recoil ceases, that is, as soon as the kinetic energy inherent in the rearwardly moving machine gun is absorbed in the two resilient media, namely the air and the helical spring 17, the machine gun begins to return to its original position.

ln its end position however it would strike al hard blow unless an air cushion were provided, which is formed by a cup-shaped brake cylinder 19, into which there extends a pistonlike prolongation 2O of the end of the piston 4.

The air compressedin the air cushion can escape past a screw spindle 21 in a throttling outlet, said spindle having acone end, so

ythat by tightening or loosening this screw spindle 21 the duration of movement of the connecting piece can be regulated within fairly wide limits. The tube 1 is slotted in front, the saddle 7 being slidable in the slotted portions, and is provided with two symmetrical lugs 22, which can be drawn together-by means of a screw, whereby also the brake cylinder 19 is secured.

Since the machine gun fitted in this manner is continually in motion when being fired, the

touching thereof by the hand of the gunner would necessarily have the result at each discharge thatA the gun would receive a lateral impulse after each shot and the direction of its aim would be continually changing. In order to obviate this the connecting piece is provided witlr a trigger 4mechanism 23, 24, 25, 26, 27, 28, 29. This device however also enables the second object of the connecting piece to be attained, that is. shooting with reduced rapidity for the purpose of economizing ammunition. An important requirement which must be complied with by this .the machine gun.

The trigger 31 is pivoted on a pin 29 which extends across the casing 301 on the upper part of the handle and is secured into one of the walls of said'casing. On each side of the trigger 31 is a link 32 which is rotatably mounted in the casing 301 by means of a pivot pin 28, one end of which is screwed into the link. The pivot pins 28 are passed through bearing holes in thev sides of the casing. The rear ends of the links 32 rest on ribs provided on each side of the` lower edge of the trigger 31, said ribs having a concave cylindrical sliding surface 33 and an inclined cam surface 34. Normally, the links 32 restl on the concave cylindrical sliding surface 33 but when the trigger 31 is pulled the lower ends of the links come into contact with the cam surface 34 which raises the rear ends of the links from the position shown in full lines in Figure 6 to the position shown in dot and dash lines. Above the links 32 is arranged a rod 35 which is connected at its rear end to the links 32 by means of links 261, which are pivoted at one end on a pivot pin 26 passed through the rod. The other ends of the links 261'are pivoted to the links 32 by means of a plvot pin 27. The rod 35 is passed through a slot 1n the trigger 31 and through a hole in a transverse wa1l351 in the casing 301 into a portion 302 of the casing containing a coil spring 36, one end of which abuts against the left-hand side of the wall 351, while thel other end engages a collar 361 screwed on to the lefthand end of the rod 35. lVhen the links 32 are raised by pulling the trigger 31, the pin 27 is moved into the position 27a and the pin 26, together with the rear end of the rod 35, into the position 26@l (Fig. 6). As

-the left hand end of the rod 35 is prevented by the spring 36 from changing its position materially, the right hand end of the rod will move practically along a circular arc having a radius equal to the length of the rod. Above the rod 35 is a bell-crank lever 38 pivoted on a pin 24 fixed to the recoiling part of the connecting piece, through one arm of which lever is passed a pin 25. The bell crank lever is operatively connected to the rear end of the rod 35 by means of links 37, through the upper ends of which passes the pin 25 and through the lower ends the pin 26. Thus, when the pin 26 moves into the position 26a the pin 25 moves into the position 25EL (Fig. 6) and rocks the bell-crank lever 38 clockwise. The free arm of the bell-crank lever extends upwardly and at its end has anotch 23 which engages the `trigger 14 of the machine gun and fires the gun when the bell-crank lever 38 is rocked clockwise by pulling the trigger 31. After a shot is fired, the pin 24 immediately begins to move rearwardly with the bell-crank lever 38 towards the position 24a, the pin 25 also moving rearwardly, whereby the pin 26 and the rod 35 is pulled to the rear and compresses the spring 36. During the rearward movement of the pin 25 the links 37 strike against slide surfaces or ramps 39 on the casing, so that the rod 35 is moved obliquely and downwardly until the pin 25 occupies the position 25b and the pin 26 occupies the position 26h. By this means a small hook 40 on the rear end of the rod 35 comes into engagement with the rear wall of the casing in the position 40a shown in broken lines in Figure 3. The bell-crank lever 38 is thereby turned a little in the anticlockwise direction and the notch 23 moves out of cnga gement with the trigger 14 and'remains out of engagement whether the trigger 31 is pulled or not. A fresh shot cannot be fired until the pin 24 has returned to its initial position. After the gun has completed its rearward movement it is returned to its runout position by means of the return spring 17 and the compressed fluid between thc pistons 4 and 5.

The run-out movement of the machine gun is checked by the fluid in the brake cylinder 19. By suitable adjustment of the spindle 2l, the return movement of the machine gun can be made to take place very slowly, thus enabling the gun to be red with reduced rapidity.

When the gun reaches its fully run out position, the handle 12 of the gun strikes against a lever 41 pivoted to the rear wall of the casing 301, thereby turning said lever to the left. The lever 41 rests against the hook 40 when the latter is in engagement with the rear wall of the casing and forces the hook out of engagement with the said rear wall when the handle 12 strikes against it, thereby allowing the spring 36 to displace the pull rod 35 to the left and return the parts of the trigger mechanism into their irlng position shown in dot and dash lines in Figure 6, provided of course that the trigger 31 is still pulled. During the return movement of the parts of the trigger mechanism, the pin 26 moves into the position 26a and rotates the bell crank lever 38 clockwise, a further shot is ired and the cycle of operations recommences. If the trigger 31 is not pulled, the parts move into the position shown in full lines in Figure 6 and the gun ceases to fire. By this means, the gun can be fired with a comparatively slow tiring speed.

The hook 40, however, can be prevented from snapping into engagement with the rear wall of the casing 301 for the purpose of enabling the gun to lire faster. For this purpose a small hook 42 is pivoted to the rear wall of the casing 301 so as to be capable of being turned up from the position shown in broken lines in Figures 1 and 3 to the position shown in full lines, so as to snap into engagement with a retaining tooth 43 on the lever 41. The lever 41 is normally moved back a short distance by the hook 40 but when the former is prevented by the hook 42 from moving back, the hook 40 rides down an incline on the lever 41 and is thereby prevented from snapping into engagement with the rear wall of the casing 301. By this means the spring 36 is not retained in its compressed state when the moving part ofthe recoil mechanism returns to its run-out position and thc machine gun will therefore be fired by the trigger 14 coming into contact with the notch 23 immediately the gun returns to its run-out position. The gun then lires with its normal rapidity.

It is unnecessary to remark that it is absolutely essential that the axis of the tubes 1 and 4 be made exactly parallel to the axis of the machine gun barrel. lt obviously seems necessary to give the spring 17 in its initial position a stress which is at least equi alent to the weight of the machine gun employed, and to give the spring 36 a stress which must at least overcome the trigger pressure of the gun employed, for otherwise these springs could not keep the machine gun in the correct position, when firing at aircraft for example, nor could they e'ect the discharge of the gun in the event of the rapidity of shooting being so much slackened that the lll) litt) CII inertia eiects of the moving masses were no longer eiective.

What We claim is l. A connecting piece for securing automatic fire arms of small calibre to fixed mountings, comprising in combination a part adapted to be rigidly but releasably secured to the mounting, a part adapted to be rigidly but re` leasably secured tothe gun, elast-1c recoil absorbing means connected to said parts and adapted to permit the gun to move rearwardly with respect to the mounting under the force of the recoil after each shot and to return the gun to its original position with respect to the mounting, a grip and a trigger mechanism on the part of the connecting piece secured to the mounting, said trigger mechanism havlng a member movable into engagement with the trigger of the gun, so as to actuate the gun trigger on the gun moving lnto its run-out position.

2. A connecting piece for securing automatic fire arms of small calibre to fixed mountiugs, comprising in combination a part adapted to be rigidly but releasably secured to the mounting, a part adapted to be rigidly but releasably secured to the gun, elastic recoil absorbing means connected to said parts and adapted to permit the gun to move rearwardly with respect to the mounting under the force of the recoil after each shot and to return the gun to its original position with respect to the mounting, a grip and a trigger mechanism on the part of the connecting piece secured to the mounting, said trigger mechanism comprising a member mounted on the part of the connecting piece secured to the gun and movable into engagement with the trigger `of the gun, so as to fire the gun only when the gun occupies its fully runout position, said member being adapted to move out of engagement with the trigger on the gun moving rearwardly of its fully runout position.

3. A connecting`piece for securing automatic fire arms of small calibre to iixed mountings, comprising in combination a part adapted to be rigidly but releasably secured to the mounting, a part adapted to be rigidly but releasably secured to the gun, elastic recoil absorbing means connected to said parts and adapted to permit the gun to move rearwardly with respect to the mounting under the force of the recoil after each shot and to return the gun to its original position with respect to the mounting, a grip and a trigger mechanism on the part of the connecting piece secured to the mounting, said trigger mechanism comprising a. trigger mounted on the part of the connecting piece secured to the mounting, a member adapted to actuate the gun trigger pivoted on the part of the connecting piece secured to the gun, links operatively connected to said trigger on the connecting piece and to said member for transmitting motion from the former to the latter, a pull rod operatively connected to the said links so as to be capable of turning said member from a position in engagement with the gun trigger to a position out of engagement therewith, and a spring operatively connected to said rod so as to urge it forward but capable of yielding to allow the rod to move rearwardly on the gun recoiling, so as to move said member out of engagement with the gun trigger.

4. A connecting piece for securing automatic :tire arms of small calibre to fixed mountings, comprising in combination an outer cylinder having means adapted to secure it rigidly but releasably to the mounting, an inner cylinder slidable inside said outer cylinder and having means adapted to secure it rigidly but releasably to the gun, apiston inside said inner cylinder and rigidly connected to the outer cylinder, said inner cyl-- inder being adapted to slide on said piston, elastic recoil absorbing means between the outer and inner cylinders, adapted to yield in Order to allow the gun to move rearwardly with respect to the mounting when a shot is fired and to return the gun to its original position with respect to the mounting when the force of the recoil is spent, a casing and a grip on the rear of said outer cylinder, a brake cylinder in the forward end of said outer cylinder into which said inner ed to project at the end of the run-out of the gun, a trigger mechanism in said casing having a member movable into engagement with the trigger of the gun, so as to actuate the gun trigger on the -gun moving into its run-out position.

5. A connecting piece for securing automatic fire arms of small calibre to fixed mountings, comprising in combination an youter cylinder having means adapted to secure it rigidly but releasably to the mounting, an inner cylinder slidable inside said outer cylinder and having means adapted to secure it rigidly but releasably to the gun, a piston inside said inner cylinder and rigidly connected to the outer cylinder, said inner cylinder being adapted to slide on saidv piston, elastic recoil absorbing means between the outer and inner cylinders, adapted to yield in order to allow the gun to move rearwardly with respect to the mounting when a shot is vfired and to return the gun to its original position with respect to the mounting when the force of the recoil is spent, a casing and a grip on therear of said outer cylinder, a brake cylinder slidable in the forward end of said outer cylinder into which the inner cylinder is adapted to project at the end of the run-out of the gun, a slot in the forward end of said outer cylinder, lugs on said forward end, one on each side of said slot, a clamping screw passed through said lugs for contracting the forward part of the outer cylincylinder is adaptder, a trigger mechanism in said casing having a mem er movable into engagement with the trigger of the gun, so as to actuate the gun trigger on the gun moving into its runout position.

6. A connecting piece for securing automatic fire arms of small calibre to fixed mountings, as set forth in claim 3, and having a casing enclosin the trigger mechanism above the grip, a catc hook on the rear end ofthe pull rod adapted to engage the said casing in the rearward movement of the pull rod, and means on said casing adapted to disenage said hook from the casing, said means Eeing actuatable by the gun on the latter moving into its run-out position, so as to release the pull rod to move the trigger of the connectlng piece into operative engagement wlth -the trigger of the gun.

7. A connecting piece for securing auto-Y matic' fire arms of small calibre to fixed mountings, as set forth in claim 3, and having vsaid lever and force it forward as the gun moves into its eXtreme forward position, so

as to disengage the catch hook from the casing and release the pull rod to move the trigger of the connecting piece into operative engagement with the trigger of the gun.

8. A connecting piece for securingautomatic fire arms of small calibre to fixed mountings, comprising in combination a part adapted to be rigidly but releasably secured to the mounting, a part adapted to be rigidly but releasably secured to the gun, elastic recoil absorbing means connected to said parts and adapted to permit the gun to move rearwardl with respect to the mounting under the force of the recoil after each shot and to return the un to its original position with respect to le mounting, a grip and a trigger mechanism on the part of the connecting .piece secured to the mounting, said trigger mechanism comprising a trigger mounted on the part of the connecting piece secured to the mounting, a member adapted to actuate the gun trigger pivoted on the part of the connecting piece secured to the gun, links operatively connected to said trigger on the connecting piece and to said member for transmitting motion from the former to the latter, a pull rod operativel yconnected to the said links so as to be capa le of turning said member from a position in engagement with the gun trigger to a position out of engagement therewith, and a spring operatively .Connected to said rod so as to urge it forward but capable of yielding to allow the rod to move rearwardly on the gun recoiling, so as to move said member out of engagement with the gun trigger, said spring having an initial stress greater than the pressure, exerted on the pull rod by the trigger of the 9. A connecting piece for securing automatic fire arms of small calibre to fixed mountings, as set forth in claim 3, and having a casing enclosing the trigger mechanism 4above the grip, a catch hook on the rear end of the pull rod adapted to engage the said casing in the rearward movement of the pull rod, and a lever pivoted on said casing so as to lie in the path of said catch hook, said lever being displaceable rearwardly by the hook so as to allow the pull rod to engage the casing, means on the gun adapted to engage said lever and force it forward as the gun moves into its extreme forward position, so as to disengage the catch hook from the casing and release the pull rod to move the trigger of the connecting piece into operative engagement with the trigger of the gun, a hook pivoted on the casing and adapted to engage the said lever so as to lock it and preventrearward movement of the lever by the catch hook and prevent the catch hook from engaging the casing.

In testimony whereof we have signed our names to this specification. 

